Recharge your LiFePO in-bike or out? Battery bag?

[SubRider]

So,

Do you pull your LiFePO battery off your bike when you recharge it?
Or do you leave it attached to your bike when you recharge it?

Do you ride with your LiFePO in a battery bag?

 

[e-beach]

So,

Do you pull your LiFePO battery off your bike when you recharge it?
Or do you leave it attached to your bike when you recharge it?

Do you ride with your LiFePO in a battery bag?

Hey SubRider! First things first....


OK, now that that is done...

I have my LiFePO4's mounted into my e-bike. I leave them there when I ride and when I charge. They are Headways. Been very dependable so far. Almost 8000 miles so far. My BMS is in the bike also.

 

[amberwolf]

see the links to my build threads in my signature for my answers.

 

[dogman dan]

Much depends on your climate, and where you park the bike. As far south as I live, I have to bring all batteries inside for the summer, where it's not over 100F. It can get to 120 easy in the garage.

So all summer the chargers are in the house. But when it's cooler, I leave safe to charge batteries on the bike, but unplugged from the controller, and charge there in the garage. Once it gets really cold, it's back to keeping them inside, so they will be at 60F when I start riding. Too much sag and capacity loss leaving the house with a 30F battery.

I sometimes carry them in a bag, sometimes in a box. ALL batteries have a protective inner box, that I usually make by cutting and taping coroplast, that plastic cardboard they make political signs out of. This protects them from chafing and damage in the box or bag. Makes them more crash resistant.

One thing I never do, is build the battery permanently onto the bike. But my reason for this is I always have 4-6 ebikes ready to ride. So the battery hops from bike to bike constantly.

 

[Triketech]

LiFe batteries are pretty much fault tolerant and given a good BMS you should be able to charge as installed. They are beginning to be used to replace SLA starting batteries on airplanes and temps range from very cold (some have onboard pre-start heaters) to very hot, temps in the 120°+ range.

On the other hand if the battery is merely shrink wrapped in a bag and the BMS is of unknown quality all bets are off.

 

[SubRider]

Thanks folks.

But hey--my battery IS shrink-wrapped in a bag!

I got it from Sun Huck (sun-thing28, sun-thing, et.al.).
Does anybody know how good their BMS is?

How common is it for riders to swap out the stock BMS in their shrink-wrap bag?
What are good BMS units?

 

[dogman dan]

If it's working, your bms is fine.

Wrap it in something stiff, so it can handle it if the bike falls over without dinging the soft pouch cells in your pack. Masonite, plastic tote box lids, political signs, whatever. Just make it a super tight fitting protective box.

In the garage, yes, you can leave it there when it's hot. But storing it in hot garage shortens it's lifespan. So if convenient, bring it inside when it's crazy hot outside. When it's crazy cold, you will get longer range if you start the ride with a battery that is room temp.

When it's room temp in the garage, you can leave it on the bike all you want. I just want my batteries out of the garage if it's going to hit 90F or more.

 

[SubRider]

Thanks Dan.

Hey, what is the key material that battery bags are made out of?
This would be the fire proof or resistant material, correct?
Or are battery bags just waterproof?

 

[dnmun]

you should open the shrink wrap on your sunthing guy pack and pull the BMS out into the air and i recommend removing all the shrink wrap and putting end plates on the pack and then putting it into compression to extend cycle life.

the BMS can be improved by adding a switch in the circuit current of the BMS so you can turn off the battery and stop the spark when you connect it to the controller. you should add a wire to the current collector ground plane for the drains of the output mosfets. that will add a lot of reliability.

 

[LewTwo]

This would be the fire proof or resistant material, correct?

Not very likely. My guess would be some kind of polymer.
My point is make no assumptions.
Unless otherwise stated assume the cheapest material available was used.